As a countermeasure to prevent global warming, attention is being given to effective utilization of biomass's own energy. Among others, plant-derived biomass energy can effectively utilize carbon fixed from carbon dioxide in the atmosphere by photosynthesis in the course of growth of plants and therefore has the property of so-called carbon neutral, which does not lead to increase of carbon dioxide in the atmosphere, from the viewpoint of life cycle. Moreover, also from the viewpoint of depletion of petroleum resources, rise in crude oil price, etc., biomass fuel is viewed as a promising alternative energy to oil.
In the field of transportation fuel as well, using such biomass energy has been studied. For example, if using animal or vegetable oil-derived fuel as diesel fuel becomes possible, it is expected to play an effective role in reduction of emission of carbon dioxide by virtue of the synergistic effect with high energy efficiency of diesel engine.
Fatty acid methyl ester oil (abbreviated to “FAME” from the initials of Fatty Acid Methyl Ester) is known as animal or vegetable oil used in diesel fuel. FAME is produced by subjecting triglyceride, which is a general structure of animal or vegetable oil, to transesterification reaction with methanol by the action of an alkali catalyst or the like. This FAME has been studied for its use not only in diesel fuel but also in aviation fuel oil, so-called jet fuel. Aircraft are greatly influenced by rise in crude oil price of recent years, because their fuel use is enormous. In such a situation, biomass fuel has received attention not only as prevention of global warming but also as a promising candidate of alternative fuel to oil. Under such circumstances, mixed use of FAME to petroleum-based jet fuel has been practiced currently on a trial basis in several airline companies.
However, the process of producing FAME requires processing of secondarily produced glycerin, as described in the Patent Literature given below. Moreover, problems such as cost or energy required for washing of produced oil, etc., have been pointed out.